Most notable among a variety of differences between normal and transformed cells is a loss of the cell matrix and association of matrix proteins with the cell membrane. Fibronectin and collagen are major components of the cell matrix and confer increased adhesion to cells. We have shown that low levels of glucocorticoid hormones (e.g., dexamethasone) can revert transformed cells towards normal (dex-R plus) leading to the development of an extracellular matrix of fibronectin and collagen. We will perform numerous studies to attempt to document the mechanism for this fundamental change induced by dexamethasone. We will ascertain whether dex can revert cells transformed in a variety of manners, and also tumors existing in man or animals. We will document whether dex modifies other phenotypic characteristics of cells and whether it is acting directly or functioning in some permissive role with other hormones or factors.